Machine for honing a gear



April 13, 1965 K. J. DAVIS 3,177,623

MACHINE FOR HAVING A GEAR Filed Oct. 1, 1962 FIG.I.

INVENTOR. KENNETH J. DAVIS will not be transmitted to the teeth of the tool.

. permitted. tool displacement, which may be only a few thousandths United States Patent 0 3,177,623 MACEHNE FUR HONING A GEAR Kenneth J. Davis, Detroit, Mich, assignor to National Breach & Machine (30., Detroit, Mich, a corporation of Michigan Filed Oct. 1, 1962, Ser. No. 227,290 3 Claims. (Ci. 51--1tl5) The present invention relates to a gear honing machine and is a continuation-in-part application of my copending application Serial No. 769,440, filed October 24, 1958, now Patent No. 3.088,251, dated May 7, 1963.

In gear finishing, and particularly in gear honing, it is desirable to maintain a pressure contact between the working surfaces of the teeth of the tool and the teeth of the work gear, with the axes of the tool and work gear being preferably crossed as is well known in the art. However, it is also desirable to permit a limited yielding between the tool and work gear so that excessive stresses In the case of honing such stresses may cause the hone to break down rapidly or it may even cause the teeth of the hone to break out of the tool.

The present invention was developed primarily for permitting a gear honing operation to (1) allow for substantial eccentricity in a work gear without injury to the honing tool and (2) to automatically correct such eccentricity. If a work gear when initially meshed with the honing tool had substantially eccentricity and was brought into mesh with its low side in firm engagement with the honing tool and work gear may be controlled while at the same time some yielding or displacement of the honing tool relative to its support and to the work gear is The resilient ring is very sensitive to the of an inch. This displacement of the tool results in addiional compression of the resilient ring, which may be made from rubber or other yieldable material, and hence results in an increase in pressure whenever a displacement of the tool takes place.

In addition, the use of the resilient mounting or ring in a gear honing machine gives rise to the second function outlined above; namely, correction of the eccentricity of a work gear. This, of course, is because the radial pressure acting between the work gear and hone is a function of the yieldable force exerted on the bone by the gear.

The material of the annular ring interposed between the tool and its support has been described as a yieldable resilient material such as rubber. A resin compound is used in the production of the annular toothed peripheral portion of the honing tool and is slightly yieldable and highly resilient.

From the foregoing it will of course be apparent that the nature of these two materials is essentially dissimilar. The material of the peripheral toothed 3,177,523 Patented Apr. 13, 1965 portion of the honing tool is quite hard and maintains a form except when displaced under relatively high unit pressure. When this occurs, the resilience of the material causes it to regain its initial form as soon as the high unit pressure has been removed.

On the other hand, the annular coupling ring which connects the tool support and the annular toothed peripheral portion of the tool is relatively soft and is intended to yield so as to limit the total force acting between the work gear and the gear-like honing tool to a few pounds, as for example between one and fifty pounds. Similarly, when the work gear and honing tool are in loose mesh, the annular coupling ring limits the total circumferential force acting between the gear and tool to a corresponding small range. Thus, the function of the yieldable coupling ring is to establish and maintain a relatively small average force acting between the gear and tool. This force is, of course, variable in accordance with displacement as previously described.

It is an object of the present invention to provide a honing machine comprising a tool support, a rotary honing tool having a series of teeth, the surface portions of which are of hard resilient plastic material having abrasive particles embedded therein, means comprising a substantially annular resilient coupling ring yieldably connecting the honing tool to the tool support, a work support for mounting a work gear to be finished in mesh with the teeth of the honing tool at crossed axes, means mounting one of said supports for movement toward and away from the other of said supports to apply a predetermined pressure between the honing tool and work gear carried by the supports, and means for rotating the honing tool and gear in mesh, said resilient ring being effective to maintain the tool and gear in radially acting pressure contact with each other at a pressure which varies directly in accordance with the radial spacing between the honing tool and the work gear.

It is thus another object of this invention to provide a simplified low-cost structure of the aforementioned type having certain advantages contributing to efiiciency, reliability and long life as well as ease of maintenance.

Other objects and features of the invention will become apparent as the description proceeds, especially when taken in conjunction with the accompanying drawing illustrating preferred embodiments of the invention, wherein:

FIGURE 1 is an elevational view of a novel gear honing machine.

FIGURE 2 is an elevational view of a tool and tool support constructed in accordance with the present invention.

FIGURE 3 is a fragmentary enlarged sectional view of the embodiment illustrated in FIGURE 2.

FIGURE 4 is a view similar to FIGURE 3 illustrating a second embodiment of the present invention.

FIGURE 5 is a view similar to FIGURE 3 illustrating yet another embodiment of the present invention.

FIGURE 6 is a fragmentary end view with parts broken away of the structure shown in FIGURE 5.

As mentioned previously, the present invention relates to a recent development known as gear honing in which a gear-like tool, preferably after heat treatment or other hardening operation, is run in mesh with a gear-like hone. A hone is a tool in the form of a gear having at least its toothed portions formed of a relatively hard but slightly yieldable and highly resilient resin having abrasive particles separately embedded therein.

The operation is carried out by driving either the gear or the hone in rotation thereby driving the other of the members which is mounted for substantially free rotation. During meshed rotation between the gear and bone a relative traverse is carried out in a plane parallel to the axes of both spindles orsupports to insure distribu tion of the finishing action of the hone from end to end of the gear teeth. This relative traverse is normally a direction parallel to the axis of the gear; a

To insure the pressure contact betweenth'e' teethbf example as'a natural or synthetic rubber,'or a suitable yieldable plastic. The ring 58 is highly resilient and the gear and honenecessary to produce a gear finishing 1 operation, one of the supports is mounted for movement toward and away from the other support, and means are provided for applying a tomato move the saidone sup port so as to establish an initial predetermined pressure contact between the teeth ofthe gear and home. In

addition, according to the present invention, a yieldableresilient support ring is provided which automatically compensates for any eccentricityin the work gear.

Referring now to FIGURE 1, there is shown a masupports the" toothed annular body 54 On the support body 50. Due to its ,yieldability radial'clisplacement of the annular toothed body 54 relative to the support body 50 andtool support 3 6 is permitted. I v V Asmentioned previously, thepresent invention may be ally eflicient in producing gear hones is a resin com- Hpound'form'e'd of equal parts by weight of epoxy resin chine which embodies the principle of the present inven:

tion and which isdesignated by the numeral 10. Described in general terms, the machine 10 comprises a column 16, and a forwardly projecting overhanging por-. tion 18. A vertically movable-knee jis carried by the frame'lz and at its top is provided with a slide or,

carriage 22.,

v j The knee 20 is vertically movable toaccommodategears; of difierent sizes and to provide a preliminary setting of the machine. Suitable meansi such for example as a vertically extending feed s'crewi24 is provided for effecting vertical adjustment of the knee 20, this being ac:

frame indicated gener'allyat 12 including a base '14, a

- weight' of 400. The epoxy resin is liquid. The epoxy anda relatively'fine abrasive material such for example as powdered silicon carbide. The' epoxy resin is the re sult of a; reaction between .epichlorohydrin and Bisphenol-A carriedout in the presence of 'a water solution of sodium hydroxide at atemperature of approximately 100. degrees Fahrenheit. The reaction is continued to produce-an epoxy resin having an approximate molecular value,equiv./ 100 gm. is 0.50. The hydroxyl groups per molecule are 0.14-0.28.

complished by rotation of the feed screw 24 and a nut (not shown) as controlled by a manually operable handle,

not shown, applied to the square end of an. actuating shaftv 26; The carriage 22 is mounted on suitable Ways 28 provided at the top of the knee 20 and may bemountledthereon for, reciprocation in aihorizontal plane in a direction perpendicular to the plane of FIGUREfl. In

other cases, as is well understood in the art, the direction of traverse in the. horizontal plane may be varied. I Mounted on the carriage 22' is a rotary work support means including a headstock (not sholwn) and a tail 4O honing portion of the tool .T is illustrated at 70 and instock indicated at'30. In the gear honing operation the gear G is in mesh with a. honing tool T. While the axes of the gear G and honing tool T in FIGURE 1 are-in -Resincompound Abrasive grains (46-280 grit) 100-150 ,Hardenejr (aliphatic or polyamine such as metaa phenylene diamine) This *resin compound, in order to produce the gear I honing tools having the toothedperipheral portion shown, is mixed with abrasive material and hardenerin approximately the following proportions by weight V 1 15-20 v. This m'aterial maybe readily to the solid form and 1s characterized in part-by its'dimensionalstability which permits casting to thelfinal required dimensions;

Referring now'to FIGURE 3, there is shown a support'bo d y 60 having'a hub 62" and radially extending flanges 64. An intermediate annular support body 66 is illustrated herein as fastened to the support body 60 by screws .68. The annular toothed'gear finishing or eludes gear-liketeeth 72 anda continuous annular body dicated as parallel, in practice the axes of'these members will be crossed in ,space 'normally at'an angle of between three and thirty degrees. The tool T is. carried by an angularly adjustablehe'ad '32,'the head .32 being mounted for adjustment about. a vertical ,axis' to vary 1 the crossedaxes sett ngfibetween the gear G and tool portion 74. Intermediate the annulor body 74 and the support" body 66 is a yieldable'suppor't ring 76 which may "-be formed ofnatural 'nubbe -synthetic rubber or a' suitable plastic'material." The vpa'rts'maybe assembled in therelationship shown in FIGUE 3 by maintaining the.

' rubber or other suitablematerial'under substantial coin- T. A motor 34 is provided and is! connected to the spindle 36 of the tool T by gearing indicated at: 38 to etiect positive ro'tati'on of, the tool T and hllCBlOnd IlVfi the gear G through the meshed engagement of the parts. 1

Normally, suitable feed means such as the'feed screw 40 and nut 42fare provided for effecting relativetraverse between thecarriage22 and the knee20.

Inorder to carry out thehoning operation. under sufii cientpressure contact to remove material from the sur 7 face of the hardened teeth. of the. gear ,G the knee 20 1 ismoved upwardly'to bring the teeth of; the gear Giin'to mesh with the teeth of the tool T under an initial predetermined pressure aswillbeexplained in more detail later on in the specification. I V Referring to FIGURE 2, there is shown the tool-'1 'p'ression while the annular'body" 74 is assembled to surround it and thereafter releasing the rubber. i h It will, of course, be appreciated that the yieldable supjiwport ring' 76 permits limited radial circumferential and a axial displacement between the bodies 66 and 74. v The amount "of resistance which the' support ring 76'fopposes -to displacement of the annular body 74 on thesupport body '66 may be controlled as desired.'f Ajprim'ary conf-trol isinf the compounding of the? material of the support ring 76- The radial dimension or.;thickness of the ring is', of course, also effective to influence itssupporting action. Finally, thedegree of initial. compression of the ,-ani1ular support ring enters into its effectiveness as a 1 support,"

mounted on the support'36 andcomprising an inner support body 50 of circular cross-section, the support body 50 having a centrally located hole 5 2 by means of which it may be mounted on the tool support 36.. Located concentrically with the support body 50 and spaced radi- In gear finishing, and particularly in gear honing, it is desirable to maintain a pressure; contact between the working surfaces of the teeth of the tool T and the teeth f-ofthe 'gear G. However-,; it is also desirable'to permit alirnited yielding s o'that excessive stresses will not be transmitted to the teeth of the tool T. In the caseof ally outwardly'therefmm isan annular'toothed body 54,

the peripheral 'portions offwhich are p rovide d with; teeth; '56 which may be conjugate tothe teeth of the gear j to be finished. The annular toothed body=54 is separated; radially from the outer peripheral portion of the sup-1. port body 50 and thisspace is filled With-.an annular coupling ring 58 formed-of a yieldabl material such for honing such stresses may icause'the. hone to breakdown port ring such as the. ring 76, the average operating pressurebetween, the teeth'of the tool and gear may be controlled while'at the same time some yieldingv of the tool Trelative to the' work gear Gis permitted. Thisyielding results in additional compression of the rubber or other yieldable material and hence results in an increase in pressure whenever a displacement of the toothed portion of the tool T takes place.

This is an important feature of the present invention. Consider for example the situation which may exist when the gear G and tool T are brought into mesh with initial contact at the low side of an eccentric work gear G. During rotation, as the high side of the gear G meshes with the teeth of the tool T, the tool T is displaced away from the gear, thus preventing injury or breakage of the tool T. However, this displacement of the tool T results in an increased pressureproportional to the amount of displacement so that the metal removing action of the tool T is thus in turn proportional to the displacement. Since this displacement is the result of an error which is to be corrected, the tool T automatically provides its greatest corrective action at the portions of the work gear exhibiting the greatest error, or in other words, the portions of the work gear G which require the greatest finishing action. The resilient ring 76 is very sensitive to displacement of a magnitude of only a few thousandths of an inch.

Referring now to FIGURE 4, there is provided a support body 80 having a radially extending flange portion 82 provided at its outer edge with a radially extending projection 84. The support body includes a hub 86 to which is secured a guide ring 88, the connection being illustrated as retained by screws 90. At its outer edge at the side thereof facing the flange 82 the guide ring 88 is provided with a radially extending projection 91. Mounted between the flange 82 and the guide ring 88 is a support ring or core 92 which may be of metal or plastic and which is surrounded by the toothed annular body '94 having the gear finishing teeth 96 formed thereon.

The body 94 may be formed of the resin compound previously described in detail. The support ring 92 is mounted on the hub 86, and interposed between the hub 86 and the support ring 92 are a plurality of yieldnot shown, between ring 92 and flange 82. v Referring now to FIGURES 5 and 6, there is illus-J trated another embodiment of the present invention in which a support body 101 is provided with an annular peripheral recess 102 adapted to receive a yieldable and resilient coupling ring 104. The recess 102 is defined between the side flanges 105 and 106 of the support body 101. The flanges 105 and 106 include a plurality of separated guiding extensions 107 and 108 respectively. The annular toothed body 110 which may be formed of the abrasive containing resin compound previously described, is herein illustrated as having its inner portion received between the extensions 107 and 108 but terminating outwardly from the tops of the continuous portions 105 and 106. The extensions 107 and 108 constitute guides permitting limited radial displacement of the annular toothedv body 110 while preventing wobble or displacement thereof axially of the support body 101. Torque transmission may be by radial key means, of the type illustrated in FIGURE 4, provided between body 110 and extensions 107.

It will be observed in these figures that the yieldable material is substantially but not completely trapped in a chamber formed on three sides by the recess 102 and at its outer side by the annular toothed body 110. Means are provided for varying the effectiveness of the yieldable a predetermined pressure contact. and gear G are driven in mesh as described previously.

support ring 104 and this means comprises rings 112 each of which has a plurality of circumferentially separated fingers 114 slidable through slots in the flanges and 106. The rings 112 and fingers 114 are adjustable by means of screws 116 extending through the rings 112 into the support body 101. It will be apparent that inward movement of the rings 112 causes the fingers 114 carried thereby to displace material of the yieldable support ring 104 and thereby to increase its resistance to radial displacement of the annular toothed portion 110. A yieldable rubber, which may be employed as the material of the ring 114, is not essentially compressible and it is for this reason that the flanges 105 and 106 are provided with the extensions 107 and 108 respectively. These extensions are circumferentially separated as previously "described, and thereby provide openings into which the yieldable material of the support ring 104 may be displaced by inward movement of the fingers 114.

As mentioned previously, materialof the yieldable ring interposed between the central core and the relatively rigid annular toothed portion has been described as a yieldable resilient material. The resin compound used in the production of the annular toothed peripheral portion of the tool has also been described as slightly yieldable and highly resilient. From the foregoing it will, of course, be apparent that the nature of these two materials is essentially dissimilar. The material of the peripheral toothed portion of the tool is quite hard and maintains a form except whenv displaced under relatively high unit pressure. When this occurs, the resilience of the material causes it to regain its initial form as soon as the high unit pressure has been removed.

On the other hand, the annular coupling ring which connects the central core and the annular toothed peripheral portion is relatively soft and is intended to yield so as to limit the total force acting between the gear and the gear-like tool to a few pounds, as for example between one and fifty pounds. Similarly, when the gear and gear-like tool is in loose mesh, the annular coupling ring limits the total circumferential force acting between the gear and tool to a correspondingly small range. Thus, the function of the yieldable coupling ring is to establish and maintain a relatively small average force acting between the gear and tool. of course, variable in accordance with displacement which may be only a few thousandths of an inch as previously described.

It is desired to emphasize the fact that the tota force acting between the gear and tool is quite a different matter from the unit pressure between the toothed surfaces of the gear and tool. It will be appreciated that when a high spot of limited area is present on a tooth of the gear, it may exert an extremely high unit pressure on corresponding portions of the mating teeth of the tool as it moves in mesh therethrough. This, however, will in most cases not substantially influence the total radial or circumferential force acting between the tool and gear as a whole.

By way of a specific example, a yieldable coupling ring of approximately one inch thickness and having a radial dimension of approximately one-half inch may be formed of a good grade of rubber, either natural or synthetic,

having a Shore durometer of 40-80.

It should be understood from the foregoing description that when the present invention is utilized in a honing operation, the work gear G is moved vertically on the slide 22 by means of the feed screw 24 so that the gear G is brought into mesh with the tool T under Later on the tool T As the teeth of the hone wear, the knee 20 is moved vertically upwardly to maintain the predetermined pressure contact.

The drawings and the foregoing specification constitute a description of the improved machine for honing This force is,

agear in such full, clear, concise, and exactrterms as to enable any person skilled in the art to practice'theinven- V yhoning tool-and work gear carried by: said supports,

tion, the scope of whicha-tj indicated "appended ms-1 w H HWhat'Lclairn as'my invention is:

-1. A gear honing. machine comprising a V a e ifi r6 .tary tool support on said frame, ahoning tool'onsaid meansfori rotating said honing tool and work gear in mesh atidentical pitch jline velocity, and means including 'saidj'resili'en't ring responsive'automatically ,to any eccentricity in the work ge'ar to provide; for displacement lof said honing toolfin a lateral direction away from said tool support, said honing tool being in the fo'rmoi a f at least theqtoothed surface portions of saidhoning toolbeing formed of an abrasive material, a rotary work' support for mounting a work gear, means providing for relative approach-and separation between .the work gear I gearhavingteethconjugate to the teeth of-a work gear; 10

workfgear to Supplement said initial predetermined pressurewith; a pressure which varies directly in I accordance with the radial. spacing between. saidztool and workgear as determined by .the amount ofteccentricity in the work gear, saidjva'riable pressure being 'efiective t ,o "produce changes in' the rate of material removed frgr'nsaidzwork gear; and to correct 7 the eccentricity in said work .gear. 7

carried by said work support and thehoning fool carried by said tool supportincludingsmeans -for ,applying'an initial predetermined pressurerbetween said to olfand work gear, and means-responsive-to .thesmallvariations in center distance between the work gear and honing tool resulting from rotation of'an eccentric work gear to provide variations in pressure effective to fremove inaterial more rapidly from ,the teeth fofi thework. gear at the high side thereof so as topr'ovide a correctionifo'f eccentricity; i i

2. A honing machine comprising a tool support, a .rd- V ftary honing tool having a series 'ofteeth, at least the tooth surface portions of -which are formed of, an'

abrasive material, means comprising Qa substantially annularresilient coupling ring under initial compression 3'. The honingmajchine defined in "claim 2;wherein .said honing "tooland saidiwork gear are in mesh with each other atj'crqssed axegandmeans are provided for effectingrelatives traverse between said supports in a plane parallel to'the axes of lpothpof said supports and i in a direction'in suchplanefwhich is non-parallel to the 20.

A i l ererencj CitedEhytheEkaniiner" i 7 ,UNIT D STATESJPATENTS v j 1 :i nsTE i/rswn o E,Pr.i m a r y Exziuninerg I 

1. A GEAR HONING MACHINE COMPRISING A FRAME, A ROTARY TOOL SUPPORT ON SAID FRAME, A HONING TOOL ON SAID TOOL SUPPORT, SAID HONING TOOL BEING IN THE FORM OF A GEAR HAVING TEETH CONJUGATE TO THE TEETH OF A WORK GEAR, AT LEAST THE TOOTHED SURFACE PORTIONS OF SAID HONING TOOL BEING FORMED OF AN ABRASIVE MATERIAL, A ROTARY WORK SUPPORT FOR MOUNTING A WORK GEAR, MEANS PROVIDING FOR RELATIVE APPROACH AND SEPARATION BETWEEN THE WORK GEAR CARRIED BY SAID WORK SUPPORT AND THGE HONING TOOL CARRIED BY SAID TOOL SUPPORT INCLUDING MEANS FOR APPLYING AN INITIAL PREDETERMINED PRESSURE BETWEEN SAID TOOL AND WORK GEAR, AND MEANS RESPONSIVE TO THE SMALL VARIATIONS IN CENTER DISTANCE BETWEEN THE WORK GEAR AND HONING TOOL RESULTING FROM ROTATION OF AN ECCENTRIC WORK GEAR TO PROVIDE VARIATIONS IN PRESSURE EFFECTIVE TO REMOVE MATERIAL MORE RAPIDLY FROM THE TEETH OF THE WORK GEAR AT THE HIGH SIDE THEREOF SO AS TO PROVIDE A CORRECTION OF ECCENTRICITY. 